What types of content you can create or edit depends on the privileges assigned to the "role" or user group that you're a member of. In general, to find out what you can do:

• On your user menu (the collection of links that has your user name as a title), look for a link that says "create content." Click this to get a listing of the types of content you have permission to post.
• On most pages, look for links in a red sidebar on the right or in tabs at the top of an article. If one of these links says "edit", you have permissions to add and edit that type of content.

Red sidebar management links

Tabbed management links